Expert: Bruce E. Johnson - 10/24/2009

Question
There is a water leak originating from the area where the chimney flashing meets the roof. the water is running down behind the stucco chimney and into the basement. From the basement looking up you can see the joists and subflooring under the fireplace are water damaged and subfloor has mold so we want to remove the subfloor. Can the subflooring be replaced from the basement below without having to remove or damage the fireplace or flooring of the first floor?

Answer
Hi John, I suppose you could take a sawzall and cut between the joists, up through the subfloor and drop out the subfloor from underneath and then attach side cleats to new sections of subfloor, push up the new piece of subfloor into place and screw the cleats to the sides of the joists.  You would still have a strip of the old subfloor on the top of the joists.  When you say the material is damaged do you mean just esthetically?  or serious rot and deterioration?  Mold can be cleaned with soap and water and then sprayed with a bleach solution to kill remaining spores, then treated with an antifungal solution to keep it from coming back.  If the floor is rotten and the joists are rotten you may need to replace everthing before it all comes crashing down or at least add new joists alongside the old ones to prevent such a catastrophe. Of course before attempting a permanent fix I would make sure the leak has been properly taken care of...I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com